1. Multiple Deposit Expansion
David Mayer AP Macroeconomics Winston Churchill High School North East ISD San Antonio, TX

2. Reserve Requirement
The Fed requires banks to always have some money readily available to meet consumers’ demand for cash.
The amount, set by the Fed, is the Required Reserve Ratio.
The Required Reserve Ratio is the % of demand deposits (checking account balances) that must not be loaned out.
Typically the Required Reserve Ratio = 10%

3. The Money Multiplier
The money multiplier shows us the impact of a change in demand deposits on loans and eventually the money supply.
To calculate the money multiplier, divide 1 by the required reserve ratio.
Money multiplier = 1/ reserve ratio
Ex. If the reserve ratio is 25%, then the multiplier = 4.
Why? 1/ .25 = 4

4. The Three Types of Multiple Deposit Expansion Question
Type 1: Calculate the initial change in excess reserves
a.k.a. the amount a single bank can loan from the initial deposit
Type 2: Calculate the change in loans in the banking system
Type 3: Calculate the change in the money supply
Sometimes type 2 and type 3 will have the same result (i.e. no Fed involvement)

5. The Three Types of Multiple Deposit Expansion Question
Oops!!!! Type 4: Calculate the change in demand deposits

6. Example 1
Given a required reserve ratio of 20%, assume the Federal Reserve purchases $100 million worth of US Treasury Securities on the open market from a primary security dealer. Determine the amount that a single bank can lend from this Federal Reserve purchase of bonds.
The amount of new demand deposits – required reserve = The initial change in excess reserves
$100 million – (20% * $100 million)
$100 million – $20 million = $80 million in ER

7. Example 2
Given a required reserve ratio of 20%, assume the Federal Reserve purchases $100 million worth of US Treasury Securities on the open market from a primary security dealer. Determine the maximum change in loans in the banking system from this Federal Reserve purchase of bonds.
The initial change in excess reserves * The money multiplier = max change in loans
$80 million * (1/20%)
$80 million * (5) = $400 million max in new loans

8. Example 3
Given a required reserve ratio of 20%, assume the Federal Reserve purchases $100 million worth of US Treasury Securities on the open market from a primary security dealer. Determine the maximum change in the money supply from this Federal Reserve purchase of bonds.
The maximum change in loans + $ amount of Federal Reserve action
$400 million + $100 million = $500 million max change in the money supply

9. Example 4
Given a required reserve ratio of 20%, assume the Federal Reserve purchases $100 million worth of US Treasury Securities on the open market from a primary security dealer. Determine the maximum change in demand deposits from this Federal Reserve purchase of bonds.
The maximum change in loans + $ amount of initial deposit
$400 million + $100 million = $500 million max change in demand deposits

10. Review Required Reserve = Amount of deposit X required reserve ratio
Excess Reserves = Total Reserves – Required Reserves
Maximum amount a single bank can loan = the change in excess reserves caused by a deposit
The money multiplier = 1/required reserve ratio
Total Change in Loans = amount single bank can lend X money multiplier
Total Change in the money supply = Total Change in Loans + $ amount of Fed action
Total Change in demand deposits = Total Change in Loans + any cash deposited